The present invention relates to a safety lock for folding chair, and more particularly to a safety lock that may be conveniently produced by way of integral injection molding and enables quick and easy operation to a lock or a release position.
A folding chair usually includes a seat located between two lateral sides of U-shaped front and rear leg frames, two armrests movably connected to upper ends of the front and rear leg frames, and knuckle members for pivotally connecting a backrest to the leg frames or the armrests, such that the backrest, the seat, and the leg frames may be turned about the knuckle members to a folded and flat state for storage, or an extended state for use. Many children""s chairs are in the form of such folding chair.
It is very possible a young and active child improperly applies a force to unexpectedly collapse the folding chair, and is unfortunately clamped between and injured by the collapsed chair. Therefore, there have been developed safety devices particularly for children""s folding chairs to avoid undesired injury of children by the collapsed folding chairs.
U.S. Pat. No. 6,062,639 discloses a locking device for movably mounting at a rear end of the seat frame of the folding chair, so that the locking device may be backward turned about a pivot point to a release position, or forward turned to a lock position to bear against a joint of a lower end of the backrest and the seat frame. That is, when the locking device is turned to the lock position, it prevents a folding knuckle of the folding chair from turning and accordingly prevents the whole chair from unexpected collapsing to clamp and injure a small child using the chair. Thus, a portion of the locking device bearing against the folding knuckle must have sufficient strength and resistance to prevent the folding chair from collapsing. For this purpose, the locking device being forward turned to the lock position must firmly bear against and clamp the seat frame in a tight fit relation to prevent the locking device from undesirably loosening from the seat frame.
To use the folding chair with the above-described locking device, it is necessary to extend the chair and turn the locking device to the lock position, and to turn the locking device to the release position before collapsing the chair. Since the locking device in the lock position firmly clamps on the seat frame, a relatively large force is required to turn it away from the seat frame to the release position. Moreover, since the locking device mounted to the rear end of the seat frame is located in a very small space at the joint of the lower end of the backrest and the seat frame, even an adult would have to apply a considerably large force to turn the locking device within the small space. The conventional locking device disclosed in U.S. Pat. No. 6,062,639 is inconvenient for use.
A primary object of the present invention is to provide a safety lock for folding chair that may be integrally injection-molded for mounting on two laterally opposite sides of the folding chair, and enables quick and easy operation thereof between a lock and a release position.
To achieve the above and other objects, the safety lock for folding chair according to the present invention mainly includes a top portion and two lateral wall portions to define an open-bottomed receiving space therebetween. The receiving space has an inner width corresponding to an outer diameter of a seat frame tube of the folding chair to which the safety lock is to be mounted. A rear end of the top portion is cut out to form a recess, and two opposite shaft holes are provided at rear ends of the two lateral wall portions below the recess. The safety lock is designed for mounting to a rear end of the seat frame tube of the folding chair, such that the rear end of the seat frame tube is located between the two lateral wall portions to extend across the open-bottomed receiving space and the recess at the top portion, and the two opposite shaft holes at the rear end of the wall portions are aligned with two through holes preformed on the seat frame tube for a shaft pin to extend therethrough and pivotally connect the safety lock to the seat frame tube. And, the two lateral wall portions have two bottom edges, at where a user pushes the safety lock between a lock and a release position, being always located at finger accessible open positions to facilitate easy push of the safety lock.
In a preferred embodiment of the present invention, the two lateral wall portions of the safety lock are provided on two outer surfaces with two laterally outward extended flanges, so as to form two expanded end surfaces at a front end of the safety lock and provide increased contact surfaces at the bottom edge of the lateral wall portions to facilitate easy application of force with fingers when pushing the safety lock.
In another preferred embodiment of the present invention, the two lateral wall portions are provided on inner surfaces at predetermined positions with two opposite pads that are adapted to tightly press against the seat frame tube when the latter is extended across the receiving space and clamped between the two lateral wall portions.